The CEA-708-D standard (see, e.g., http://www.ce.org/Standards/browseByCommittee_2525.asp, incorporated herein by reference in its entirety) defines Digital TV closed captioning as used in Digital TV systems (ATSC, DVB, Cable), etc. Newer Digital TV systems provide a 3D rendering capability which provides for depth projection of Video content during playback through use of polarized glass and lens technology and/or shuttered glasses.
One problem present in such systems today is that there does not exist a means to specify, using existing CEA-708D captioning technology, the depth for which the on-screen display of caption data shall be rendered.